Compilare: user.c: In function ‘calcul’: user.c:5:9: warning: variable ‘p’ set but not used [-Wunused-but-set-variable] int p,j,i; ^ user.c: In function ‘main’: user.c:15:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum.in","r",stdin); ^ user.c:16:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum.out","w",stdout); ^ user.c:18:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.c:21:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&k); ^